Heating and quenching apparatus



March 16, 1948. J, oux 2,438,064

HEATING AND' QUENCHING APPARATUS Filed Jan. 28, 1942 2 Sheets-Sheet 1 grwe/wto'n JOHN H. LOUX 2 Sheets-Sheet 2 J. H. LOUX Filed Jan. 28, 1942 HEATING AND QUENGHING APPARATUS March 16, 1948.

JOHN H. LOUX Patented 16;, 1948 HEATING AND QUENCHING APPARATUS John H. Loux, Salem, Ohio, assignor to The Salem Engineering Co roprietorship mpany, Salem, Ohio, a

Application January 28, 1942, Serial No. 428,557 8 Claims. (01. 266-4) This invention relates to continuous heating furnaces and more particularly to furnace equipment for'hardening, oil quenching, drawing and water quenching metal objects and to this end involves a novel hardening furnace and drawing furnace arrangement together with an improved system for handling and transferring the metal objects in their path of movement through the furnaces and quenching tanks of the assembly.

A primary object of the invention is the provision of an apparatus for the purpose defined above which is economical in construction costs and space requirements but which nevertheless is capable of treating the individual objects at a high rate of production. The apparatus is so designed and constructed that an accurate timetemperature cycle may be maintained and maximum use is made of the facilities involved sub stantially at all times whereby a high overall efiiciency of the assembly may be maintained.

A further object of the invention is the provision of an improved arrangement for propelling the individual objects through the furnaces and quenching tanks of the apparatus mentioned above whereby a maximum rate of production may be maintained and uniform results may be attained in the final product.

Another object of the invention is the provision of an improved arrangement and apparatus for propelling rounded objects through a continuous metal heating furnace of conventional design. In accordance with the invention the rounded objects, which may be shell casings, are allowed to roll directly on rails extending longitudinally of the furnace. The objects are batched, preferably in pyramidal relation, in frames or trays which are open at their tops and bottoms and as these trays are pushed through the furnace, the objects are caused to roll therein and this operation results in two distinct advantages. First, the objects, by reason of their rolling motion, will be uniformly heated throughout the circumferential extent of their side walls and second, by tiering or pyramiding the objects, more objects may be placed in the furnace at one time than would be the case if all the objects rested directly on the hearth or rails of the furnace. The use of the trays facilities the charging of the furnace and also the discharging thereof or the guiding of the objects into a quenching tank depending on the particular use to which the furnace is put.

The above and other objects and advantages of the invention will become apparent from a consideration from the following detailed specifh.

cation and the accompanying drawings wherein there is specifically disclosed a preferred embodiment of the invention.

In the drawings:

Figure 1 is a plan view, partly in section, of a heat treating apparatus constructed in accordance with the principles of the invention;

Figure 2 is a longitudinal section along the line 11-11 of Figure 1; and

Figures 3 and 4 are plan views of trays which may be utilized in the same furnace or furnaces to handle large and small sized objects, respectively, such as artillery shell cases, for example.

The apparatus of Figures 1 and 2 utilizes a hardening furnace l0 and a drawing furnace H, which furnaces are identical and more or less conventional in construction. In accordance with usual practice the furnaces may be constructed with a steel shell lined with insulation and refractory material and may be fired with either liquid or gaseous fuel. Suitable temperature controlling means may be incorporated in each of the furnaces to maintain the temperature in the hardening furnace at approximately 1575" F. and an operating temperature in the drawing furnace of approximately 1150 F. In each of the furnaces two pairs of alloy steel rails [2 extend longitudinally of the furnace, and outside of the outer rails l2 are the guide rails I 3 each having a vertical guiding flange l4. Intermediate the innermost rails I2 is a guiding rail [5 having a vertical flange l6 which extends above the upper surfaces of the rails l2 but not as high as the upper surfaces of the outer flanges l4.

The furnaces l0 and H are of the pusher type in which hydraulic cylinders l7 operating rams II! are employed to intermittently push the material through the furnace. A charging platform I9 is located at the charging end of the hardening furnace l0 and a chute 20 extends downwardly and outwardly from adjacent the other end of the furnace. The rails l2 terminate above the entrance of the chute 20 and in the chute 20 are two gravity operated flap doors 2| which are adapted to swing upwardly to allow the rounded objects to roll down the chute but after the objects pass they move to vertical closing positions as shown in Figure 2.

The drawings illustrate a preferred embodiment of the invention as applied to the heat treating of explosive type armour piercing projectiles. The same assembly may be employed to treat projectiles of different calibres and Figures 3 and 4 illustrate a manner in which this object may be accomplished. Reference numeral 22 designates projectiles of smaller size, say 75 mm. while reference numeral 23 designates projectiles of 105 mm. size. The projectiles are contained within compartmented trays which are open at their tops and bottoms as explained above. The smaller projectiles or objects are arranged in two-compartment trays 24 which are of a width to fit closely between the center guiding flange [6 and one of the outer guide flanges [4 in the furnaces. The trays and compartments are arranged as illustrated in Figure 4 and within each of the compartments are five projectiles or objects, three resting directly on the rails l2 and two superimposed in pyramidal relation on the lower three. For the larger objects 23 a larger three-compartment tray 25 is employed which tray has a width to fit between the two outer guide flanges l4. Each of the compartments in the trays 25 also contains five projectiles or objects and in both types of trays the depths of the compartments, i. e. in a direction longitudinal of the furnaces, are such that the projectiles or objects will rotate freely as the trays are moved through the furnaces. The rotation of the lower projectiles will, of course, impart rotation to the upper projectiles, the depth of the compartments being restricted to prevent a wedging action between the projectiles and between the projectiles and the trays. To withstand the high temperatures encountered in the furnaces the rails, guides and trays are constructed of alloy steel containing substantial proportions of chrome and nickel. The trays may be either fabricated or cast.

Each end of each furnace is provided with a vertical lift door 26 which may be automatically operated as is well known and arranged in the discharge end of each of the furnaces is a series of tray run-out rolls 21. These rolls are arranged to beintermittently operated to propel the trays out of the furnaces. In operation the trays are loaded with the projectiles or other objects on the charging platform l9 and in proper timed sequence the doors 26 are opened, the rolls 21 are rotated, and the pusher i8 is actuated to push the previously loaded trays into the furnace, to move the trays in the furnace, and to move the last tray onto the rolls 21. The pusher then retracts, the doors close and the rolls 2'! stop automatically. During this cycle as the last loaded tray moves over the entrance to the chute 20, the objects contained therein fall out and roll down the chute. The supporting rails l2 are terminated at the entrance to the chute, as explained above, to permit this operation.

Chute 20 discharges into an oil quenching tank 28 which is kept filled with quenching oil maintained at the desired temperature. Extending from below to above the surface of the oil is a conveyor 29 provided with pockets 30 which pockets are each of a size to receive one of the objects. The discharge end of the chute 20 extends below the surface of the oil to immediately above the conveyor 29 and as the objects come down the chute they are deposited in the pockets 30 of the conveyor 29. The fiap doors 2| protect the oil from the radiant heat of the furnace and the chute 20 is provided with a water cooled section (not shown) to prevent heat flow from the furnace to the oil. The drive for the conveyor 29 is so arranged that the conveyor normally moves at slow speed but when, however, the pusher i8 is actuated the conveyor moves at high speed a sufiicient distance to transfer all the objects in the chute to the conveyor. As soon' as this is accomplished the conveyor stops and an adjustable timer initiates its cycle of operation to time the quenching period. This period may be of the order of four to six minutes and upon the termination of this period the conveyor is started up and it continues to move at its lower speed to withdraw the objects from the bath and later to deposit them on a transfer table 3i.

From the conveyor 29 the objects being treated pass onto the transfer table or cross conveyor 31 which in turn deposits the objects onto a conveyor 3i which moves the objects into positions adjacent the charging platform 33 of the drawing furnace H. The trays 24 or 25, however, are by-passed directly from the discharge end of the hardening furnace ID to the charging platform 33 by means of a transfer bug y 34 which rolls on tracks 35 and which is adapted to be shuttled between the discharge end of furnace l0 and the charging platform 33 of drawing furnace H by suitable automatic driving means, not shown.

It will be understood that the rail arrangement in the furnace H is identical with that in the furnace l0 and that the furnace II is provided with a discharge chute, tray run-out rolls, and doors so that the operation of the furnace H is substantially identical with that of the furnace I0. As the trays reach the charging platform 33 of the drawing furnace ll, an operator transfers the objects from the conveyor 32 into the trays and at properly timed intervals, preferably synchronized with the operation of the pusher for the hardening furnace ill, the pusher for the drawing furnace H is actuated to move the material into and through the furnace l l. The doors and run-out rolls of the furnace l l are automatically operated in the same manner as are the corresponding parts of the furnace ID. The objects, upon reaching the end of the drawing furnace fall into the chute thereof onto a conveyor 36 which extends from below the surface of the water in a water quench tank 31. The conveyor 36 may be operated in the same manner as is the conveyor 29 of the oil quench assembly. From the conveyor 36 the objects are deposited on a transfer table 38 for movement away from the described assembly.

Interconnecting the discharge end of the drawing furnace II and the charging platform 19 of the furnace ID are rails 39 on which travels a buggy 40, the purpose of which is to transfer the empty trays from the discharge end of the furilagce I l to the charging platform IQ of the furnace The apparatus described above is preferably arranged for substantially automatic operation and to this end the movements of the various operating parts thereof are synchronized in accordance with a predetermined cycle of operation. The initiation of each cycle may be accomplished by actuation of the pusher l8 of the furnace l0. To provide the proper heating time, which in the case of 75 mm. projectiles is approximately 4 hrs, a timer may be employed to control the periodic operation of the pusher. It should be apparent that the short closed path of travel of the trays as distinguished from the longer path of travel of the objects being heated and the manner in which the trays are moved makes for orderly and emcient operation of the assembly. Moreover the complex task of moving the objects being treated through the various component parts of the assembly is accomplished with a minimum amount of. manualhandling and attention.

Inasmuch as the rounded objects are intermittently turned during their traverse through the furnaces, they become uniformly heated thereby enabling amore accurate control to be maintained over the treating operation. Substantially improved results are attained by the practice of the invention and such results are uniform throughout the individual objects as well as between successive objects passing through the apparatus. The arrangement for moving and handling the rounded objects as taught by the invention is of practical advantage since it makes for flexibility in the operation of a furnace or of the assembly.

The above specifically described embodiment of the invention should be considered as illustrative only as obviously many changes may be made therein without departing from the spirit or scope of the invention. The invention is considered to reside in the combination as a whole as well as in certain component parts thereof. Reference should therefore be had to the appended claims in determining the scope of the invention.

What I claim is:

1. In heat treating apparatus having an elongated hardening furnace, a quench tank adjacent the discharge end of said furnace, and an elongated draw furnace having its charging end adjacent the discharging end of the hardening furnace and its discharging end adjacent the charging end of the hardening furnace, the combination of a plurality of object carrying trays adapted to propel the objects being treated through said furnaces, means to push said trays through said furnaces, means to empty said trays into said tank at the discharge end of said hardening furnace, means to transfer said trays directly from the discharge end of said hardening furnace to the charging end of said draw furnace, and means to convey the objects being treated from said quenching tank to adjacent the charging end of said drawing furnace.

2. In heat treating apparatus having hardening and drawing furnaces of the pusher type and a quenching tank intermediate thereof, the improvement which comprises arranging said furnaces in inverse parallel relation whereby the discharge end of said hardening furnace is positioned adjacent the charging end of said drawing furnace and vice versa, a circuitous support extending through the heating chambers of said furnaces and interconnecting the discharge end of the hardening furnace with the charging end of the drawing furnace as well as the discharging end of the drawing furnace with the charging end of the hardening furnace, a plurality of open bottomed trays each adapted to contain metal objects to be heat treated mounted for movement on said circuitous support in succession, the hearths of said furnaces being each provided with openings near the discharge ends of the respective furnaces whereby the heated objects are emptied from the trays before the trays pass out of the respective furnaces.

3. Apparatus according to claim 2 further characterized in that said hearth opening in said hardening furnace discharges said objects into said quenching tank, each of said furnaces having a tray loading platform adjacent its charging end, and a conveyor to transfer the objects from said tank to a position adjacent the loading platform of the drawing furnace.

JOHN H. LOUX.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Roth Sept. 2, 1941 

